1. Field of the Invention
The present invention relates to an improvement in an analog timepiece in which both hours and minutes are designated on a circular face by a single hand.
2. Description of the Prior Art
The conventional configuration for the portion of an analog timepiece that imparts information to an observer is well known and has not changed significantly for centuries. The conventional configuration of such a timepiece takes the form of a watch or clock having a face with indicia corresponding to hours of time arranged at uniform angular intervals about a central location on the face. Normally the indicia corresponding to hours on the face of the timepiece delineate, in the aggregate, a twelve hour period. Each hourly interval extends an angular distance of thirty degrees as measured from the center of the face of the timepiece. The twelve angular intervals for the hours from one through twelve cover the entire 360 degree circumference of the face of the timepiece.
According to the conventional configuration of analog timepieces the minutes within an hour are either not indicated by indicia at all, or are indicated by indicia arranged in a circular pattern at the same distance from the center of the face of the timepiece as the indicia corresponding to hours of time. With this conventional practice two different hands are mounted at the center of the face of the timepiece and are driven at different angular speeds in a clockwise direction. The two different hands extend radially out from the center of the face of the timepiece and are mounted on different drive mechanisms at the center, one atop the other.
According to convention, the shorter of the two hands is driven at the rate of one complete revolution every twelve hours, thereby pointing to a specific hourly interval within a total twelve hour period for only one hour during that twelve hour period. The longer hand of the timepiece, on the other hand, is driven at the rate of one complete 360 degree revolution every hour, and therefore makes twelve complete revolutions during the twelve hour period in which the shorter hand of the clock makes a single revolution. Thus, there are two entirely different frames of reference associated with the manner of observing the passage of time in hours and minutes in the conventional analog timepiece configuration.
To perceive the time of day using a conventional timepiece, an observer mentally associates the position of the shorter of the two hands relative to the face of the timepiece with a particular hour of the day. This association is performed with respect to a reference point which is the top of the face of the timepiece as viewed by the observer. Therefore, when the shorter of the two hands is angularly displaced 90 degrees from the top of the face and is pointed toward the indicia associated with the third hourly interval, the observer mentally recognizes that the hour is three o'clock in a twelve hour time period. Similarly, when the shorter of the two hands is angularly displaced 120 degrees clockwise from the top of the face of the timepiece, the observer recognizes that the hour is four o'clock in a twelve hour time period.
However, to perceive the minutes between two sequential hourly indicia the observer must make a change in the frame of reference. Thus, if the shorter of the two hands is angularly displaced clockwise from the top reference point between 180 degrees and 210 degrees and the longer of the two hands is angularly displaced 60 degrees, the observer must make a determination of hours and minutes using two completely different frames of reference. The position of the shorter of the two hands must be recognized as indicating some time between the sixth and seventh hour of the time period, while the position of the longer of the two hands must be recognized as indicating some fraction of a one hour interval.
In the foregoing example, the position of the longer of the two hands at a 60 degrees clockwise displacement relative to the top reference point must be considered as a fraction of the entire 360 degree pattern of a single array of indicia, which is a fraction of one sixth. Since there are sixty minutes in an hour, this fraction equates to a period of ten minutes. These combined determinations place the time at ten minutes after the hour of six. Thus, the observer utilizes the entire 360 degree circumference of the array of indicia on the timepiece in two different ways. That circumference first symbolizes an entire twelve hour period, when considered with reference to the shorter of the two hands. However, it also symbolizes a one hour period when considered with reference to the longer of the two hands.
Timepieces are available in which the circumference of the timepiece face corresponds to a twenty four hour period, rather than a twelve hour period. In such timepieces the frame of reference in determining minutes within an hour remains the same as for twelve hour timepieces, but each hourly increment corresponds to an angular travel of fifteen degrees, rather than thirty degrees in determining hours within the twenty four hour period. The principles governing the different frames of reference for determining the hours and minutes are the same, however, whether the entire circumference of the face of the conventional timepiece is considered to be twenty four or twelve hours.